JP7182137B2 - Antenna device and communication device - Google Patents

Description

The present disclosure relates to antenna devices and communication devices.

Patent Literature 1 discloses an antenna device using an artificial magnetic conductor (hereinafter referred to as AMC).

JP 2015-70542 A

The present disclosure provides an antenna device and a communication device that achieve both broadening of the operating frequency band and improvement of antenna gain even in an arrangement surrounded by a metal structure.

The present disclosure includes a feeding antenna conductor, a non-feeding antenna conductor, a ground conductor, a first artificial magnetic conductor narrowly provided by the feeding antenna conductor, the non-feeding antenna conductor and the ground conductor, and the first and at least one second artificial magnetic conductor arranged side by side with the artificial magnetic conductor and conducting with the ground conductor.

Further, the present disclosure includes an antenna device, a front panel that protects a display unit, and a window opening larger than a housing of the antenna device, and is surrounded by the window opening and fixed to a part of the front panel. a metal frame surrounding the antenna device, the antenna device comprising: a feeding antenna conductor; a non-feeding antenna conductor; a ground conductor; Provided is a communication device having a narrowly arranged first artificial magnetic conductor and at least one second artificial magnetic conductor arranged side by side with the first artificial magnetic conductor and conducting with the ground conductor.

Advantageous Effects of Invention According to the present disclosure, in an antenna device and a communication device, it is possible to achieve both widening of the operating frequency band and improvement of the antenna gain even when the periphery is covered with a metal structure.

1 is a perspective view showing the appearance of a communication device equipped with an antenna device according to Embodiment 1; FIG. Front view of the upper central part of the monitor shown in FIG. The side view which shows the example of a change of the thickness of the double-sided tape which adheres the antenna apparatus and panel which concern on a comparative example. 1 is a perspective view showing the appearance of an antenna device according to Embodiment 1; A vertical cross-sectional view showing the internal structure of the antenna device viewed from the direction of the arrow AA in FIG. A diagram showing an example of the layer configuration of the antenna device according to the first embodiment. A diagram showing an example of the layer configuration of the antenna device according to the first embodiment. A diagram showing an example of a layer configuration of an antenna device according to a comparative example. Diagram schematically showing the concept of multistage AMC FIG. 4 is a diagram showing an example of a simulation result of the radiation pattern of the antenna device according to Embodiment 1; FIG. 11 is a diagram showing an example of a simulation result of a radiation pattern of an antenna device according to a comparative example; A diagram showing an example of measurement results of frequency characteristics of peak gain FIG. 11 is a diagram showing an example of a simulation result of frequency characteristics of VSWR;

Hereinafter, embodiments specifically disclosing an antenna device and a communication device according to the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided for a thorough understanding of the present disclosure by those skilled in the art and are not intended to limit the claimed subject matter.

In the first embodiment described below, the frequency of the 2.4 GHz band (for example, 2400 to 2500 MHz) is used as the operating frequency, and wireless LAN (Local Area Network) standards such as Bluetooth (registered trademark) and Wi-Fi (registered trademark) are used. An antenna device capable of compliant wireless communication will be described as an example. However, the antenna device according to Embodiment 1 may perform wireless communication in a frequency band complying with standards other than the standards described above.

FIG. 1 is a perspective view showing the appearance of a communication device SM1 equipped with an antenna device 100 according to Embodiment 1. FIG. FIG. 2 is a front view of the monitor upper central portion UP1 shown in FIG. In the following description, x-axis, y-axis, and z-axis are the directions shown in FIG. The x-axis indicates the thickness direction of the antenna device 100 or the communication device SM1. The y-axis indicates the width direction of the antenna device 100 or the communication device SM1. The z-axis indicates the longitudinal direction of the antenna device 100 or communication device SM1.

The communication device SM1 shown in FIG. 1 is, for example, a seat monitor attached to the back of a passenger seat in an aircraft capable of using Bluetooth (registered trademark) wireless communication. Note that the communication device SM1 in which the antenna device 100 is arranged is not limited to the seat monitor described above. As shown in FIG. 1, a communication device SM1 is provided with a touch panel TP1 (an example of a display unit) using a panel PNL1 made of glass or the like on the front side. It is used while sitting on the passenger seat. That is, the communication device SM1 displays data such as an image on the touch panel TP1, and accepts an operation by a user's finger or the like on the touch panel TP1. In addition, the communication device SM1 can perform Bluetooth (registered trademark) wireless communication with a communication device (not shown) such as a smartphone or a tablet held by the user via the antenna device 100. .

The antenna device 100 is fixedly arranged in the central part UP1 above the monitor of the housing of the communication device SM1, with the printed wiring board 1 (see FIG. 4) on which the antenna device 100 is mounted being surrounded by a protective resin cover CV1. be. Antenna device 100 transmits polarized waves in the 2.4 GHz band of Bluetooth (registered trademark) from the front (for example, panel PNL1) of communication device SM1 toward the front of the rear passenger seat (see FIGS. 10 and 11). (Electromagnetic waves). A detailed configuration example of the antenna device 100 will be described later.

Further, FIG. 1 shows the main part of the monitor upper central portion UP1. The monitor upper central portion UP1 is composed of a metal frame FRM1 adhesively fixed to the back portion of a panel PNL1 made of glass or the like. 1 and the panel PNL1 are omitted in FIG. The metal frame FRM1 is a hollow, substantially rectangular parallelepiped metal structure whose cross-sectional shape in the x-axis direction is a hollow, substantially rectangular shape. For example, the metal frame FRM1 in FIG. 1 has a shape in which four different rectangular metal pieces are joined by welding or the like such that their ends are perpendicular to adjacent metal pieces.

Metal frame FRM1 has an opening (for example, front window WD1) having a larger area than antenna device 100 and resin cover CV1 in the yz plane. That is, an opening (eg, front window WD1) is formed on the front side of the metal frame FRM1. Metal frame FRM1 surrounds antenna device 100 with four different metal pieces (see FIGS. 2 and 3). That is, since the antenna device 100 is surrounded by the metal frame FRM1, the antenna device 100 is easily affected by the metal, and performance as an antenna (for example, gain or frequency characteristics of VSWR (Voltage Standing Wave Ratio)) is affected. There are concerns about a decline in

For this reason, in the first embodiment, the antenna device 100 has a metal frame FRM1 formed on the front side of the antenna device 100 by the front window portion WD1 in order to suppress deterioration in antenna performance (for example, gain or VSWR frequency characteristics). The panel PNL1 is adhered to the panel PNL1 by a double-sided tape TPE1 (see FIG. 3) without any contact between the two. Thereby, the antenna device 100 and the panel PNL1 are directly fixed via the double-sided tape TPE1, and the antenna device 100 can suppress the influence of the metal frame FRM1.

FIG. 3 is a side view showing an example of change in thickness of the double-sided tape TPEz for bonding the antenna device 100z and the panel PNLz according to the comparative example. A detailed configuration example of the antenna device 100z according to the comparative example will be described later with reference to FIG.

The antenna device 100z is covered with a metal frame FRMz having a substantially U-shaped cross section in the x-axis direction, and is adhesively fixed to a panel PNLz made of glass or the like with a double-sided tape TPEz. The thickness of the front-side metal frame FRMz, which is adhesively fixed to the panel PNLz, is 2.6 mm. Since the thickness of the double-sided tape TPEz is 0.15 mm, the feed point of the antenna device 100z is located on the front side (close to the panel PNLz) with respect to the metal frame FRMz with a thickness of 2.6 mm. As a result, even if the antenna device 100z is covered with the metal frame FRMz, the antenna performance (for example, gain) does not degrade so much as can be seen from the radiation pattern RPNz from the antenna device 100z.

However, through consideration during the design process assuming actual usage records, it was found that if the thickness of the double-sided tape TPEz is 0.15 mm, the mechanical reliability when fixing the position of the antenna device 100z (for example, the antenna device 100z may be lowered). It has been found that the "hardness or misalignment" is insufficient.

Therefore, as the background to the first embodiment, the thickness of the double-sided tape TPEz is changed from 0.15 mm to 0.8 mm, and the antenna device 100 is adhesively fixed to the panel PNL1 by the double-sided tape TPE1 having a thickness of 0.8 mm. was done. Thus, it is considered that the mechanical reliability (see above) can be ensured when fixing the position of the antenna device 100z. However, since the thickness of the double-sided tape TPE1 is increased from 0.15 mm to 0.8 mm, the antenna device 100z is further separated from the panel PNLz (that is, moved in the direction b shown in FIG. 3). Become). Therefore, the antenna device 100z is affected by the metal frame FRMz (particularly, the metal frame on the front side adhered to the panel PNLz), and the radiation pattern RPNz of the antenna device 100z deteriorates.

Therefore, based on the above background, even if the back part of the panel PNL1 is adhesively fixed using a double-sided tape TPE1 with a thickness of about 0.8 mm (that is, when the antenna is separated from the panel PNL1), the surrounding metal frame Examples of antenna devices 100 (see FIG. 6) and 100a (see FIG. 7) that suppress the influence of FRM1 and suppress deterioration of antenna performance (for example, gain or VSWR frequency characteristics) will be described.

FIG. 4 is a perspective view showing the appearance of the antenna device 100 according to the first embodiment. FIG. 5 is a vertical cross-sectional view showing the internal structure of the antenna device 100 viewed from the direction of arrow AA in FIG. FIG. 6 is a diagram showing an example of the layer configuration of the antenna device 100 according to the first embodiment. FIG. 7 is a diagram showing an example of the layer configuration of the antenna device 100a according to the first embodiment. FIG. 8 is a diagram showing an example of a layer configuration of an antenna device 100z according to a comparative example. 4 to 8, the x-axis, y-axis and z-axis follow the illustration in FIG.

A dipole antenna will be described as an example of the antenna devices 100, 100a, and 100z. The dipole antenna is formed on a printed wiring board 1 which is a laminated board having a plurality of layers, and the pattern of the dipole antenna is formed by etching the metal foil on the surface. Each of the plurality of layers is made of, for example, copper foil or glass epoxy. Antenna devices 100, 100a, and 100z are configured to include at least an antenna layer L1, an AMC layer L2, and a ground layer L3.

As shown in FIG. 4, the antenna device 100, 100a includes a printed wiring board 1, an antenna conductor 2 which is a strip conductor as an example of a feeding antenna, and an antenna conductor 3 which is a strip conductor as an example of a non-feeding antenna. , and a parasitic conductor 6 arranged laterally of the antenna conductors 2 and 3 . The printed wiring board 1 of the antenna devices 100 and 100a is arranged in the monitor upper central portion UP1 of the communication device SM1 such as a seat monitor (see FIG. 1).

Antenna conductors 2 and 3 are connected to via conductors 4 and 5 of printed wiring board 1, respectively. The via conductor 4 is formed using, for example, a conductive copper foil, and is connected to a feeding point Q1 of the antenna conductor 2 and a wireless communication circuit (not shown; for example, a signal source circuit mounted on the back surface 1b of the printed wiring board 1). constitute the feeder between The via conductor 5 is formed using a conductive copper foil, for example, and constitutes a ground line between the feeding point Q2 of the antenna conductor 3 and the wireless communication circuit (not shown).

Each of the antenna conductors 2 and 3 has a substantially rectangular shape (including a rectangular shape) so as to constitute, for example, a dipole antenna, and their longitudinal directions extend in the z-direction on a straight line. In addition, the antenna conductors 2 and 3 are configured so that the ends of the antenna conductors 2 and 3 facing the feeding points Q1 and Q2 (in other words, feeding side ends) are electromagnetic waves radiated from the antenna conductors 2 and 3, respectively. are formed on the surface 1a of the printed wiring board 1 so as to be spaced apart by a predetermined distance in order to minimize the cancellation of .

Note that the ends of the antenna conductors 2 and 3 opposite to the feeding-side ends (specifically, the ends that are maximally separated from each other when the antenna devices 100 and 100a are viewed on the yz plane ) are hereinafter referred to as “tip end portions” of the antenna conductors 2 and 3, respectively.

The parasitic conductor 6 is arranged in parallel in the arrangement direction (z direction) of each of the antenna conductors 2 and 3, is arranged on one side of each side surface of the antenna conductors 2 and 3, and is electrically separated from the antenna conductors 2 and 3. It is A predetermined distance is ensured between the parasitic conductor 6 and each of the antenna conductors 2 and 3 in order to similarly minimize cancellation of electromagnetic waves radiated from each. The predetermined distance is, for example, a distance within a quarter of one wavelength of electromagnetic waves in the operating frequency band that the antenna devices 100 and 100a support. Since the parasitic conductor 6 is electrostatically coupled with the AMC 8 in the same manner as the antenna conductors 2 and 3, the electrostatic capacitance between the antenna conductors 2 and 3 and the AMC 8 is increased, and the operating frequency is shifted to the low frequency side. is possible. The parasitic conductor 6 is electrically separated from the antenna conductors 2 and 3 .

The size, shape, number, and the like of the parasitic conductors 6 are not particularly limited. There may be only the antenna conductors 2, 3 on the surface, not arranged on top.

The via conductors 4 and 5 are formed by filling conductors such as copper foil into through holes formed in the thickness direction (x direction) from the front surface 1a to the back surface 1b of the printed wiring board 1, respectively. Via conductors 4 and 5 are formed at substantially opposing positions immediately below feeding points Q1 and Q2, respectively. Since the antenna conductor 2 functions as a power feeding antenna, the antenna conductor 2 is connected to the power feeding terminal of the wireless communication circuit (see above) on the rear surface 1 b of the printed wiring board 1 through the via conductor 4 . Since the antenna conductor 3 functions as a non-powered antenna, it is connected to the ground conductor 10 in the printed wiring board 1 and the ground terminal of the wireless communication circuit (see above) through the via conductor 5 .

In FIG. 5, the printed wiring board 1 has a structure in which a dielectric substrate 7, an AMC 8 (Artificial Magnetic Conductor), a dielectric substrate 9, a ground conductor 10, and a dielectric substrate 11 are laminated. be. The laminated structure of the printed wiring board 1 is an example. Here, the dielectric substrates 7, 9, and 11 are substrates having insulating properties against DC components, and are formed of, for example, glass epoxy.

AMC8 is an artificial magnetic conductor having PMC (Perfect Magnetic Conductor) characteristics, and is formed of a predetermined metal pattern. Since the AMC 8 is electrostatically coupled to the antenna conductors 2 and 3 and the parasitic conductor 6, the antenna can be made thinner and gain higher. In the AMC 8, the intermediate portions of the via conductors 4 and 5 facing each other in the z-axis direction are penetrated in the thickness direction (x-axis direction) of the AMC 8 and extend to the vicinity of the ends in the width direction (y-axis direction) of the AMC 8. A slit 81 is formed (see FIGS. 6 to 8). In Embodiment 1, the slit 81 has a shape in which three slits are connected at the central portion in the width direction (see FIGS. 6 to 8).

In addition, the AMC 8 has a hole for the slit 81, a via-conductor insulating hole 15 formed through the via-conductor 4 and electrically insulated from the inner AMC 8i2 (see later), and a via-conductor 5 passing through. A hole electrically connected to the inner AMC 8i1 (see below) and a hole through which the via conductors V1 and V2 (see below) penetrate and are electrically connected to the outer AMCs 8o1 and 8o2 (see below) are respectively formed. It is

The via conductor 4 has a cylindrical shape and is a feeder line for supplying electric power for driving the antenna conductor 2 as an antenna. It is electrically connected to the power supply terminal of the circuit (see above). Via conductor 4 is substantially coaxial with via-conductor insulating holes 15 and 16 formed in AMC 8 and ground conductor 10, respectively, so as not to be electrically connected to AMC 8 and ground conductor 10, respectively. It is formed. Therefore, the diameter of via conductor 4 is smaller than the diameter of via conductor insulating holes 15 and 16 .

The via conductor 5 has a cylindrical shape and is a ground line that electrically connects the antenna conductor 3 to the ground terminal of the wireless communication circuit (see above). is electrically connected to the ground terminal of the radio communication circuit (see above). Via conductor 5 is electrically connected to each of AMC 8 and ground conductor 10 .

The ground conductor 10 is formed using a conductive copper foil. In the ground conductor 10, a via-conductor insulating hole 16 is formed through which the via-conductor 4 penetrates and is electrically insulated from the ground conductor 10; , a hole through which the via conductor 5 penetrates and is electrically connected to the ground conductor 10, and a hole through which the via conductors V1 and V2 (see later) penetrate and are electrically connected to the ground conductor 10 are formed. . The connector terminal connection hole 82 is provided for positioning when fixing the connector terminal of the wireless communication circuit (see above) facing the connector terminal.

Further, in the antenna devices 100 and 100a (see FIGS. 6 and 7) according to the first embodiment, compared to the antenna device 100z (see FIG. 8) according to the comparative example, the length from the antenna conductors 2 and 3 to the end of the AMC 8 is greater. In addition to the inner AMCs 8i1 and 8i2 having slits 81 at their ends, they have outer AMCs 8o1 and 8o2 that are electrically connected to the ground conductor 10 via via conductors V1 and V2, respectively, although they have different lengths. In the antenna devices 100, 100a (see FIGS. 6 and 7) according to the first embodiment, the length from the antenna conductors 2, 3 to the ends of the inner AMCs 8i1, 8i2 is 19.5 mm, and the antenna according to the comparative example In device 100z (see FIG. 8), the length from antenna conductors 2, 3 to the ends of AMCs 8i1z, 8i2z is 21.5 mm.

In other words, the difference between the antenna device 100z and the antenna devices 100 and 100a is the number (or area) of the AMC8. As a result, the number (or area) of the arrangement patterns of the AMCs 8 of the antenna devices 100 and 100a is larger (wider) than the arrangement pattern of the AMCs of the antenna device 100z by the outer AMC 8o2 or the outer AMCs 8o1 and 8o2. As will be described later, when these outer AMCs are provided, the antenna devices 100 and 100a according to the first embodiment are adhesively fixed with a double-sided tape TPE1 having a thickness of 0.8 m as shown in FIG. However, it is possible to suppress deterioration of antenna performance (for example, gain or VSWR frequency characteristics) (see FIGS. 12 and 13). As shown in FIG. 7, even when at least one of the outer AMCs 8o1 and 8o2 (specifically, the outer AMC 8o2 on the feeding point Q1 side) is provided, the antenna performance (for example, gain or VSWR It was found that it is possible to suppress the deterioration of the frequency characteristics of

The via conductors V1 and V3 have a columnar shape and penetrate the dielectric substrate 7, the outer AMC 8o1, the dielectric substrate 9, the ground conductor 10 and the dielectric substrate 11 at a distance of, for example, 19.5 mm from the antenna conductor 3. is provided as follows. Via conductors V1 and V3 are formed using conductive copper foil, and form ground lines between outer AMC 8o1 and ground conductor 10 (see FIGS. 5 and 6). The outer AMC 8o1 is provided so as to be separated from the inner AMC 8i1 via a gap 83 having a predetermined length. The gap 83 is, for example, one-eighth or less of the wavelength of the electromagnetic waves in the operating frequency band. In addition, the via conductors V1 and V3 are provided at positions spaced apart by a predetermined length from the end of the inner AMC 8i1 closest to the outer AMC 8o1 (the tip end described above). Here, the predetermined length is, for example, 1/8 or less of the wavelength of the electromagnetic wave in the operating frequency band.

Similarly, the via conductors V2 and V4 have a columnar shape, and are arranged at positions separated from the antenna conductor 2 by, for example, 19.5 mm. is provided to pass through the The via conductors V2 and V4 are formed using a conductive copper foil, and constitute ground lines between the outer AMC 8o2 and the ground conductor 10 (see FIG. 5). The outer AMC 8o2 is provided so as to be separated from the inner AMC 8i2 via a gap 84 of a predetermined length. The gap 84 is, like the gap 83, about 0.2 mm, for example. In addition, the via conductors V2 and V4 are provided at positions spaced apart by a predetermined length from the end of the inner AMC 8i2 closest to the outer AMC 8o2 (the tip end described above). Here, the predetermined length is, for example, 1/8 or less of the wavelength of the electromagnetic wave in the operating frequency band.

In the first embodiment, the provision of the outer AMCs 8o1 and 8o2 that are electrically connected to the ground conductor 10 through the via conductors V1 and V2 reduces the thickness compared to the case where the outer AMCs 8o1 and 8o2 are not provided (see FIG. 8). Even if the panel PNL1 is adhered to the panel PNL1 with a double-sided tape TPE1 having a thickness of about 0.8 mm, the influence of the surrounding metal frame FRM1 can be suppressed, and the performance (for example, gain) of the antenna device 100 can be improved in the operating frequency band (FIG. 12). reference). Further, according to the antenna device 100, it is possible to shift the operating frequency band to the low frequency side so as to match or approach the ideal operating frequency conforming to the Bluetooth (registered trademark) standard. This means that, for example, in the VSWR characteristics of FIG. 13, the operating frequency at which the minimum value (peak) is obtained shifts to the low frequency side. For example, provision of the outer AMCs 8o1 and 8o2 electrically connected to the ground conductor 10 is thought to increase the path (area) of the current flowing from the antenna conductor 3 to the AMC 8 and the ground conductor 10 .

FIG. 9 is a diagram schematically showing the concept of multistage AMC. When used in an antenna device, the AMC is formed to have PMC (Perfect Magnetic Conductor) characteristics in the operating frequency band of the antenna device. A perfect magnetic conductor has a very high surface impedance property, so that the tangential component of the magnetic field at the surface is zero. Therefore, the AMC can suppress propagation of electromagnetic waves having frequencies in the operating frequency band of the antenna device along the surface of the AMC. As a result, unnecessary radiation from the AMC to the antenna element is suppressed, and the performance of the antenna device can be improved.

Therefore, as shown in FIG. 9, AMC patterns A3, A5, . By arranging the AMC patterns A4, A6, . In other words, by arranging the AMC patterns in infinite cycles, the operating frequency band of the antenna device ILA1 can be widened, and the gain can be improved. The term "multistage" as used herein means that a plurality of AMC patterns are arranged side by side in the antenna device.

However, in such an antenna device ILA1, the number (or area) of AMC patterns is increased (widened), and there is a problem that miniaturization is difficult. For example, like the communication device SM1, the installation space of an antenna device arranged in the device is often limited.

Therefore, in the antenna device 100 according to Embodiment 1, an AMC pattern (specifically, an inner Outer AMCs 8o2, 8o1 electrically connected to the ground conductor 10 are arranged side by side with the AMCs 8i2, 8i1). That is, in the antenna device 100 according to Embodiment 1, outer AMCs 8o1 and 8o2 are added compared to the antenna device 100z according to the comparative example. Outer AMC 8o1 is electrically connected to ground conductor 10 through via conductors V1 and V3. Outer AMC 8o2 is electrically connected to ground conductor 10 through via conductors V2 and V4. As a result, in the antenna device 100, the inner AMCs 8i1 and 8i2 and the outer AMCs 8o1 and 8o2 are arranged side by side so that the AMCs 8 are arranged in multiple stages, and even if a metal structure such as a metal frame FRM1 is arranged around it, the AMCs 8i1 and 8i2 are arranged side by side. The influence is suppressed, and performance as an antenna (for example, gain or frequency characteristics of VSWR) is improved.

FIG. 10 is a diagram showing an example of simulation results of the radiation pattern PTY1 of the antenna device 100 according to the first embodiment. FIG. 11 is a diagram showing an example of simulation results of the radiation pattern PTYz of the antenna device 100z according to the comparative example. The radiation pattern indicates the strength (gain) for each azimuth (direction) of electromagnetic waves radiated from the antenna device when the position of the antenna device is the center. In each of FIGS. 10 and 11, the direction indicated by zero degrees indicates the front direction. The front direction here indicates the direction from the communication device SM1 to the rear passenger seat. As shown in FIG. 11, according to the radiation pattern PTYz of the antenna device 100z according to the comparative example, the gain in the front direction is -2.0 dBi. However, as shown in FIG. 10, according to the radiation pattern PTY1 of the antenna device 100 according to Embodiment 1, the gain in the front direction is improved to -0.8 dBi. That is, the antenna device 100 can perform high-gain wireless communication with a communication device owned by a user in the front direction.

FIG. 12 is a diagram showing an example of measurement results of the peak gain frequency characteristics PTY2 and PTY2z. The horizontal axis of FIG. 12 indicates frequency (Frequency) [MHz], and the vertical axis of FIG. 12 indicates peak gain (Peak Gain) [dBi]. A frequency characteristic PTY2 indicates the peak gain of the antenna device 100 according to the first embodiment, and a frequency characteristic PTY2z indicates the peak gain of the antenna device 100z according to the comparative example. As shown in FIG. 12, when the operating frequency band of the antenna devices 100 and 100z is the Bluetooth (registered trademark) frequency band (2400 to 2480 MHz), the peak gain of the antenna device 100z is on the high frequency side (eg, 2440 to 2480 MHz). will decrease in On the other hand, the peak gain of the antenna device 100 remains stably high in the operating frequency band targeted for wireless communication. Accordingly, the antenna device 100 can perform wireless communication with higher gain in the operating frequency band targeted for wireless communication than the antenna device 100z.

FIG. 13 is a diagram showing an example of simulation results of frequency characteristics PTY3 and PTY4 of VSWR. VSWR indicates the voltage standing wave ratio in the antenna device. The horizontal axis of FIG. 13 indicates frequency (Frequency) [MHz], and the vertical axis of FIG. 13 indicates VSWR. A frequency characteristic PTY3 indicates a VSWR characteristic of the antenna device 100a shown in FIG. 7 (that is, a configuration in which only the outer AMC 8o2 is added to the inner AMCs 8i1 and 8i2). A frequency characteristic PTY4 indicates a VSWR characteristic of the antenna device 100 shown in FIG. 6 (that is, a configuration in which both the outer AMCs 8o1 and 8o2 are added to the inner AMCs 8i1 and 8i2). As shown in FIG. 13, according to the antenna devices 100 and 100a according to the first embodiment, the range in which the value of VSWR is 3 or less (that is, the operating frequency band) is widened, and the center of the operating frequency is It is shifted to the low frequency side (for example, around 2450 MHz). Therefore, for example, it is possible to configure an antenna device compatible with the radio frequency of Bluetooth (registered trademark) (2.4 GHz band described above). That is, according to the antenna devices 100 and 100a according to the first embodiment, wireless communication corresponding to the radio frequency of Bluetooth (registered trademark) (2.4 GHz band described above) can be performed, for example.

As described above, the antenna devices 100 and 100a according to the first embodiment include a feeding antenna conductor (for example, the antenna conductor 2), a non-feeding antenna conductor (for example, the antenna conductor 3), a ground conductor 10, a feeding antenna conductor, a non-feeding A first artificial magnetic conductor (for example, the inner AMCs 8i1 and 8i2) narrowly provided by the antenna conductor and the ground conductor 10. Moreover, the antenna device 100 is provided with at least one second artificial magnetic conductor (for example, the outside AMC 8 o 2 ) that is arranged in parallel with the first artificial magnetic conductor and conducts with the ground conductor 10 . Further, the communication device SM1 according to the first embodiment includes antenna devices 100 and 100a, a front panel (for example, panel PNL1) that protects a display unit (for example, touch panel TP1), and a window opening larger than the housing of antenna device 100. (For example, a front window portion WD1) and a metal frame FRM1 that surrounds the antenna device 100 that is surrounded by the window opening and fixed to a portion of the front panel.

As a result, in the antenna device 100, 100a or the communication device SM1, at least the second artificial magnetic conductor is arranged outside the first artificial magnetic conductor, so that the AMC 8 is substantially multistage (see FIG. 9), Even if a metal structure such as a metal frame FRM1 is arranged around, the influence thereof can be suppressed, and the performance as an antenna (for example, gain or VSWR frequency characteristics) can be improved. Therefore, the antenna devices 100 and 100a can achieve both widening of the operating frequency and improvement of the antenna gain.

In addition, the second artificial magnetic conductor has a predetermined length (for example, the wavelength of the operating frequency band) from the end near the first artificial magnetic conductor (for example, inner AMC8i2) facing the feeding antenna conductor (for example, antenna conductor 2). It is electrically connected to the ground conductor 10 via via conductors (for example, via conductors V2 and V4) provided at positions separated by about one-eighth or less of the length. Thereby, since the second artificial magnetic conductor is arranged to conduct with the ground conductor 10 near the first artificial magnetic conductor, the first artificial magnetic conductor and the second artificial magnetic conductor are multi-staged The characteristics of the antenna devices 100 and 100a are improved.

Moreover, two 2nd artificial magnetism conductors are provided. Each second artificial magnetic conductor (eg outer AMC 8o1, 8o2) is arranged outside the closest first artificial magnetic conductor (eg inner AMC 8i1, 8i2). The term "outside" as used herein refers to a direction away from the antenna conductors 2 and 3 forming the antenna layer L1. Thereby, the antenna device 100 can shift the operating frequency band to the low frequency side compared to the antenna device 100a in which only one second artificial magnetic conductor is arranged (see FIG. 13).

Also, in the antenna device 100, a slit 81 is formed at the position of the AMC 8, which substantially faces the position between the feeding antenna conductor (for example, the antenna conductor 2) and the non-feeding antenna conductor (for example, the antenna conductor 3). be. Thereby, the antenna device 100 can increase the gain of the miniaturized dipole antenna.

Further, the antenna device 100 further includes a parasitic conductor 6 provided on a substrate (eg, dielectric substrate 7) on which a feeding antenna conductor (eg, antenna conductor 2) and a non-feeding antenna conductor (eg, antenna conductor 3) are arranged. . As a result, the parasitic conductor 6 increases the capacitance between the antenna conductors 2 and 3 and the AMC 8, and the operating frequency of the antenna device 100 can be shifted to the lower side. Therefore, even if the antenna device 100 is miniaturized, it is capable of transmitting and receiving radio frequency electromagnetic waves in the fundamental band (2.4 GHz band).

Various embodiments have been described above with reference to the drawings, but it goes without saying that the present disclosure is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications, modifications, substitutions, additions, deletions, and equivalents within the scope of the claims. Naturally, it is understood that it belongs to the technical scope of the present disclosure. In addition, the constituent elements of the various embodiments described above may be combined arbitrarily without departing from the gist of the invention.

Further, in the first and second embodiments described above, the antenna devices 101 and 102 are mounted in the seat monitor installed in the aircraft. However, not limited to seat monitors, for example, cordless telephone base unit or slave unit, electronic shelf label (for example, a card-type electronic device that displays the selling price of a product attached to a display shelf in a retail store), smart speakers, It may be installed in many IoT (Internet Of Things) devices such as in-vehicle devices, microwave ovens, and refrigerators.

Further, the antenna devices 100 and 100a according to Embodiment 1 described above are examples of antenna devices capable of both transmission and reception of electromagnetic waves, but they may be applied to, for example, transmission-only or reception-only antenna devices.

INDUSTRIAL APPLICABILITY The present disclosure is useful as an antenna device and a communication device that achieve both broadening of the operating frequency band and improvement of antenna gain even in an arrangement surrounded by a metal structure.

1 Printed wiring board 1a Front surface 1b Back surface 2, 3 Antenna conductors 4, 5, V1, V2, V3, V4 Via conductor 6 Parasitic conductors 7, 9, 11 Dielectric substrate 8 AMC
8i1, 8i2 inner AMC
8o1, 8o2 Outer AMC
10 ground conductors 15, 16 via conductor insulating hole 81 slit 82 connector terminal connection hole 83, 84 gap 100 antenna device L1 antenna layer L2 AMC layer L3 ground layer SM1 communication device Q1, Q2 feeding point

Claims (6)

a feeding antenna conductor;
a non-fed antenna conductor;
a ground conductor;
a first artificial magnetic conductor narrowly provided by the feeding antenna conductor, the non-feeding antenna conductor and the ground conductor;
At least one second artificial magnetic conductor arranged side by side with the first artificial magnetic conductor and conducting with the ground conductor,
antenna device. The second artificial magnetic conductor is electrically connected to the ground conductor via a via conductor provided at a position separated by a predetermined length from an end portion of the second artificial magnetic conductor facing the feeding antenna conductor and closer to the first artificial magnetic conductor. do,
The antenna device according to claim 1. The second artificial magnetic conductor is provided with two,
Each said second artificial magnetic conductor is arranged outside said first artificial magnetic conductor,
The antenna device according to claim 1. A slit is formed at a position of the first artificial magnetic conductor substantially opposite a position between the fed antenna conductor and the non-fed antenna conductor,
The antenna device according to claim 1. a parasitic conductor provided on a substrate on which the feeding antenna conductor and the non-feeding antenna conductor are arranged;
The antenna device according to any one of claims 1-4. an antenna device;
a front panel that protects the display;
a metal frame that has a window opening larger than the housing of the antenna device and surrounds the antenna device that is surrounded by the window opening and fixed to a portion of the front panel;
The antenna device is
a feeding antenna conductor;
a non-fed antenna conductor;
a ground conductor;
a first artificial magnetic conductor narrowly provided by the feeding antenna conductor, the non-feeding antenna conductor and the ground conductor;
At least one second artificial magnetic conductor arranged in parallel with the first artificial magnetic conductor and conducting with the ground conductor,
Communication device.

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